A known image reading apparatus includes a housing, a conveyor, and a reader. The housing includes a conveyance guide portion. The conveyance guide portion has a conveyance path through which a first medium and a second medium are guided. The second medium has a width smaller than that of the first medium and a thickness greater than that of the first medium. The conveyor is configured to convey the first medium and the second medium along the conveyance guide portion. The reader is configured to read an image on the first medium and the second medium that are conveyed along the conveyance guide portion. The second medium is guided in a conveyance region disposed at an end portion of the conveyance guide portion in a width direction.
The conveyor includes a first roller and a second roller configured to convey the second medium in the conveyance region in cooperation with each other. The first roller is configured to rotate on a first axis extending parallel to the width direction and to contact a first surface of the second medium. The second roller is rotatably disposed on a second axis parallel to the first axis and opposite to the first axis across the conveyance path. The second axis is separated apart from the first axis by the distance greater than the sum of the radii of the first roller and the second roller. The second roller is urged by an urging spring toward the first roller, so that distance between the first axis and the second axis may change. The second roller is configured to contact a second surface of the second medium opposite to the first surface. The second roller is placed at the same position as the first axis of the first roller in a conveyance direction of the second medium.
In the image reading apparatus, the distance between the first roller and the second roller approaching closest to the first roller is set greater than the thickness of the first medium. Therefore, in the image reading apparatus, application of conveyance force from the first roller configured to rotate, to the first medium conveyed along the conveyance guide portion is reduced.
In the image reading apparatus, the first roller is rotated while contacting the first surface of the second medium conveyed along the conveyance guide portion and the second roller urged by the urging spring is rotated following the first roller while contacting the second surface of the second medium. Thus, the conveyance force is applied from the first roller to the second medium. Consequently, the second medium is favorably conveyed in the image reading apparatus.